Outlook is running slow in Windows 10? Here’s how to fix it

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Email is a critical part of our daily lives, whether as individuals or even in business, and for IT admins or managers if emails are down, it can be challenging because it disrupts communication, so it’s their work to get it back up and running.

Outlook is currently the de facto standard email client in the corporate world, which generally works pretty well, but, all this doesn’t come without challenges in its workings.

Among the myriad of issues users face is Outlook running slow in Windows 10 – nothing can be more frustrating than slow speeds, or knowing that everything you do in Outlook will drag.

When Outlook has performance issues, it can be caused either by a corrupt or damaged PST file, an add-in that isn’t functioning, corrupt profile, or a problem with an Outlook application.

However, troubleshooting Outlook running slow in Windows 10 need not be a nightmare for you, as you can use some of the solutions listed below and resume communication normalcy for your business or job (if working remotely).

Note: If you cannot fix Outlook running slow issues or you simply want a good email client, we would strongly recommend Mailbird. A leader on the market, it will satisfy all your needs in mailing management.

1. Open in Safe Mode

Hold down the CTRL key when opening Outlook until the message appears. You can also right click Start, select Run, type exe /safe and press Enter

If Outlook is slow in Safe Mode, then an Add In could be causing the issue.

Click File

Select Options

Click Add In’s.

Scroll down to Manage

Click Go, and on the next screen displayed, remove the check marks

Disable all add-ins.

Start Outlook normally again and see if it works. If so, enable the add-ins one by one until Outlook fails again. The add-in you last enabled is most likely the cause of your issue. Uninstall or reinstall the specific troublesome add-in.

Most Windows users don’t know how easy is to add Safe Mode to the boot menu. Find out how you can do it in justa couple of steps.

If there is more than one PST file, look for the one with the checkmark (default)

Go to the path shown in the Data Files window, e.g. C:UsersstellaxxxxxAppDataLocalMicrosoftOutlook

Go to Show hidden files, folders and drives and uncheck Hide extensions for known file types

Save a backup copy of the PST file to safe location or removable storage

Rename the .pst extension to .psp

Open Outlook again

Click OK twice when prompted during start up to create a new PST file. If Outlook opens successfully and there are no performance issues, then the original PST file is the problem. If however, the new generic PST file shows the same issues, then either it is a corrupt profile or Outlook is damaged. In which case, repair your Outlook profile (described in the next solution)

Rename the .psp file back to .pst

Run the scanpst.exe tool on the original file and test. Outlook shouldn’t be running for this process.

Try opening Outlook again

If you want to open hidden file in Windows 10, follow the simple steps from this guide.

6. Remove whatever causes the PST to bloat up

When Outlook is running slow in Windows 10, it could be because of the piled up documents, notes, calendar entries and attachments, among other files in the Outlook PST, which make it too large in size, so it starts dragging in terms of speed and performance.

In this case, you need to offload the PST file, by doing the following:

Find a folder called Larger than 100 Kb

Delete all unwanted old emails (with bulky attachments). Save attachments you need to the disk but remove them from the PST.

Delete all other unwanted emails

Clear out the Trash.

Archive your emails by year to relieve the PST file

7. Disable RSS feeds

Outlook syncs RSS feeds from Internet Explorer by default, to its RSS reader, so if you have many bookmarked feeds, the syncing could slow down Outlook.

Go to Options>Advanced and disable this feature by unchecking both options under the RSS feeds.

8. Download complete items

Outlook should be set up to download full and complete messages when connected with IMAP or POP3, so that it doesn’t have to sync with the server each time you click on a new email or item.

Look for the Download Complete Item Including Attachments setting to enable this.

9. Update Windows

Windows Updates for Office are also ‘hidden’ so you need to allow these to install because sometimes Microsoft updates Exchange, and this can break or cause issues with the Outlook-Exchange communication.

Check also for patches issued by Microsoft for Outlook to resolve speed issues or other problems.

If you can’t open the Setting app, take a look atthis article to solve the issue.

10. Reduce calendars

Outlook running slow in Windows 10 can be worsened by more data, which Outlook is forced to pull from the Internet, so it drags. You can have one or two shared calendars, but more data means a sluggish Outlook.

11. Use Cached Exchange Mode

This takes the data file from the PST and caches it on your OST, hence speeding up Outlook as it won’t have to read its data file via a network, but through a locally stored data file.

However, you can only enable this option when connecting Outlook with Exchange server.

12. Archive inbox messages

Millions of email users, including Outlook, have thousands of emails – usually unread – in their inbox, which can cause serious problems when using PST files. You can set up auto-archiving so that the Inbox only retains some of those many emails.

Keep current and previous months’ emails in your Inbox folder, and the rest of them, just archive. This creates a new data file, which relieves Outlook of having to strain from an oversized PST/OST file.

13. Keep PST file compact

If the PST file goes overboard, you can use a tool to keep it under control. To do this:

Go to Account Settings

Click Data files

Select the data you want to compact

Click Settings

Select Advanced

Click Outlook Data File settings

Click Compact Now

14. Disable add-ins

Any add-ins can slow down Outlook. Here’s how to find out add-ins installed in Outlook:

Open Outlook

Go to Options

Click Add-ins

Select COM add-ins from the drop down

Click Go, which displays the list of all available Outlook add-ins

Find the suspect add-ins and uncheck their corresponding boxes

Were you able to fix Outlook running slow in Windows 10 using the solutions above? Let us know in the comments section below.